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    User name fansler

    Log entry time 13:36:58 on October 06, 2009

    Entry number 293477

    keyword=Hall A Trips

    We went into the hall to investigate multiple magnet trips. We found the left Q1 relief valve going off. The electronics on the cold return valve were failing causing it to open and close arbitrarily. This in turn caused an overpressure problem in the magnet affecting the lead flows of LQ1, and subsequently all lead flows. The lead flow interlocks tripped forcing the magnets into fast shut down, which caused the liquid level to boil off and the cryostats to empty. We have opened the cold return valve on the LQ1 and unplugged the valve to prevent further interruptions in operations. As a safeguard we unplugged the return valves on both Q1's cold returns verified open, warm returns verified closed. If these valved need to be moved, the hall A technical staff will have to restore power. We also discovered that the Q1 and Dipole lead flow read backs have an offset. The numbers displayed on the GUI are 8 SLM higher that the actual lead flow. We adjusted the lead flows per the front panel read back. We will investigate the lead flow offset, and make corrections as required.